The invention relates to a commutator machine such as a small direct-current motor. A machine of this kind, in particular a small direct-current motor, is known from DE-OS No. 28 45 264 or from DE-PT No. 31 19 782. In these machines there was a limit as to how much the various machine dimensions could be varied, in particular because of the demagnetization stability of the ferrite material used, and there was a tendency, with increasing motor size, to provide a percentage increase in the armature diameter as well, while reducing the optimal magnet heights by a percentage. Known calculation methods for such permanent-magnet-excited commutator machines allowed optimizing production costs on the one hand, and weight per unit of power on the other, only within narrow limits.